Investigation on energy-saving distillation for separating tetrahydrofuran/methanol/water ternary azeotropic system

The separation of ternary wastewater, with relatively high methanol and low tetrahydrofuran, from the production of 1,4-butanediol via maleic anhydride is a challenging separation issue in chemical or pharmaceutical engineering nowadays. Here we strive to explore an efficient separation method to recycle the wastewater. The triple-column extractive distillation with concentration column (TED), pressure-swing azeotropic distillation process combining of the concentration column (PSAD) and the reactive coupling pressure-swing azeotropic distillation (RCPSAD) encompasses ethylene oxide (EO) hydration reaction is presented. A simultaneous optimization strategy is proposed to optimize the parameters through the non-dominated sorting genetic algorithm (NSGA-III) taking the economic and environment indexes as the objectives, and the exergy analysis is adopted to evaluate the thermodynamic efficiency. Results show that the pressure-swing azeotropic distillation process (PSAD) is superior in terms of total annual cost of 2.46 × 106$/y and CO2 emissions of 0.90 × 107 kg/y when compared to the other two processes and the reactive coupling pressure-swing azeotropic distillation (RCPSAD) with the exergy efficiency of 54.72 %, making it the most energy-saving process. Providing a paradigm of sustainable separation of THF/methanol/water with low content of key components.